Transmission system



June 10, 1930. c. L. GOODRUM TRANSMISSION SYSTEM Filed Aug. 22, 1927 //VVENTOR.'

, CHARLES L. 6000mm. BY

ATTORNEY Patented June 10, 1930 UNITED STATES PATENT OFFICE A CHARLES L. GOODRUM, or'nnw YORK, N. Y., AssIeNoR 'ro BELL TELEIRHONE LABORA- TOR-IE5, INCORPORATED, ornnw YORK, n. Y., A CORPORATION or new YORK TRANSMISSION SYSTEM Application filed August 22, 1927. Serial Slim-214,566.

This invention relates. to transmission sys- 1 tems and particularly to systems combining station on a program receiving set, or to seboth telephone and program distribution servlce.

Its object is to simplify. the operation from the subscribers viewpoint and to otherwise improve the service re'ndered-him.-

A feature of the invention is a system in which a subscribers dial controls automatic switches at the central oflice to select a de sired program, which is received at his subfor indicating the number of subscribers listening to a program", including an indicating instrument and means effective to shunt a portion of the resistance in circuit therewith each time a subscriber listens in on the program. i

The drawing discloses a combined telephone and program distribution system, showing a subscribers line and a portion of the central office equipment.

The subscribers line 1 is equipped with the usual substation set 4 and also with a program receiving set includin a loud speaking receiver 2 and'an ampli er 3 which may be of any suitable design. The substation is also provided with an impulse transmitter.

The line 1 at the central oflice terminates in a line switch 26, which may be of any suitable type. The line switch 26 has access to trunks reaching connectors such as the connector C shown in detail. 7 If desirable, intermediate selector switches. may be'inserted between the line switch and the connector.

The connector switchC has a plurality of brushes 44 to inclusive which engage corresponding rows of terminals in the terminal bank. These brushes are stepped vertically to select a desired level of terminals and then .set of terminals in the level.

rotate horizontally to choose any particular The brushes 45 and 46 have access to successive program equipments 51, 52, etc, which may be of any suitable type. The equipment 51, for exam- 5 ple, serves to transmit a given program. The equipment 52 serves to transmit another pro-, gram. Likewise, as many equipments may be provided as there are-programs to be sent at any given time. The brushes 45 and 46 also 0 have access through other terminals-in the same or in diflerent levels through circuits and 61 to an operators board 56.

' The brush 44 engages contacts connected to the interrupters 53, 54, 55, etc. While the 05 switch-is in connection with a given program equipment a corresponding interrupter 1s included in the circuit of brush 44 to cause the operation of the subscribersmeter 34.

The rate at which the meter is operated is go determined by the class of program being received. rThe brushes 47 and 48 engage contacts associated with the measuring instruments 57, I These instruments are for indicat- 58, etc. ing the number of subscribers listening to a given program at any particular time.

If the subscriber wishes to receive any particularprogram, he manipulates hisimpulse transmitter, thus causing the'connector switch C to select the equipment for transmitting that program. While a program is being received, the polarized relay 5 is in the position shown, disconnecting the telephoneset 4 and including the receiving set in circuit with the line. If, however, the subscriber wishes to converse with another subscriber or with the operator, to secure information, for instance,

regarding the programs, he may do so by v dialing a number which sets the connector switch 0 on a trunk leading to the operators position. In response to seizing the operators position, the current is reversed over the line, operating the relay 5-to-d1sconnect the program receiving set and connect the telephone set 4 to the line.

A detailed description will now be given of the manner in which thesystem-operates.

Assume that the subscriber wishes to receive the program being sent from the equipment 10&

52. To initiate the call he presses the key 8 inward. The movement of the key 8 bends the spring 22 which is attached to one arm of the escapement lever 17. The bendingof the spring 22 stores energy therein to rotate the escapement lever 17 upward. The lever 17, however, is held in the position shown by its engagement with the lower notch in the escapement s ring 13. The curvature on the key 8 passes eyond the spring 9-holding the key in its inward position, maintaining the spring 22 in its deflected position. The spring 22 also closes the contacts 23- and 24.

The closure of springs 23 and 24 completes a bridge across the tip and .ring conductors of the line 1. This bridge may be traced from the tip conductor of line 1, thence through the windings of relay 5, through the amplifier 3, bottom contact of relay 5, contacts 23 and 24, thence through the impulse contacts 10 and 11 to the ring side of the line 1. The closure of the line initiates the operation of the line switch 26 in the usual manner and the switch 26 operates to seize a trunk leading to an idle connector switch C. As soon as the connector is seized, a circuit is closed from battery through the left winding of relay 27, lower contact of relay 36, thence over the ring side of the line and returning over thetip side of the line through the upper contact of relay 36, right winding of relay 27 to ground. Relay 27 operates and closes arf obvious circuit for the slow release relay 28.

The subscriber now manipulates his dial to transmit the first series of impulses to operate the connector C in a vertical direction to select the desired level of terminals. As the dial rotates to its forward position, the pin 15, which is secured thereto, engages the cam surface 16 of the lever 14. This tiltsthe lower arm of the lever 14 to the left deflecting the spring 12. This has no effect, however, upon the escapement lever 17 During the return motion of the dial'6, the impulse springs 10 and 11 are repeatedly opened and closed by the impulse wheel 7. Each opening and closing of the impulse springs causes the release and reenergization of the impulse relay 27. When the dial returns to its normal posltion,

the pin 15 engages the other side of the camp surface 16 tilting the lever 14 in the opposite direction. This deflects the escapement spring 13 so that the lever 17 escapes from the lower notch of said spring and is caught and heldby the notch on the escapement spring 12.

Relay 27 on releasing completes a circuit from ground through its back contact, front contact of relay 28, and thence in parallel through thewind-ing of slow release relay 29 and side switch arm 41 in its first position and i the winding of vertical stepping magnet 31 to battery. Relay 29 operates and remains enered during the series of impulses. For each impulse the magnet 31 operates and steps the brushes of the connector C up one step. At

first forward movement of-the dial the pin 15 again engages the lever 14 deflecting the spring 12 and allowing the lever 17 to escape. The lever 17 is caught by the upper notch on the escapement spring 13. On the return movement of the dial the impulse springs are opened to cause the repeated operation of the impulse relay 27. As the dial approaches its normal position the pin 15 tilts the lever 14 in the opposite direction deflecting the spring 13 and allowing the lever 17 to fully escape until it is stopped by the stop pin 19. In this position the lever 17 closes the springs 20 and 21 for a purpose which will presently be explained.

During the second series of impulses, relay 27 completes a circuit from ground through its back contact, front contact of relay 28 and thence in parallel through the winding of relay 29 and the side switch lever 41 in its second position and the winding of the rotary stepping magnet 32 to battery. The magnet 32 rotates the brushes of the connector C from position to position. At the end of the series circuit of magnet 3O, permitting the side switch to move into its third position. In position 3 of the side switch the tip and ring After an interconductors of the subscribers line are extended through arms 38 and 39, brushes 45 and 46 and terminals 63 and 64 to the program distributing equipment 52.

While the subscriber is listening to the program, a circuit iscompleted from ground through the interrupter 54, terminal 62, brush 44, wiper 37, through the line switch 26, and the winding of the register 34 to battery. At each closure of the interrupter 54 a count is made on the register 34.

With the wiper 40 in position 3 a circuit is completedfrom terminal 65, brush 47, wiper 40, brush 48 to the terminal 66. This circuit shunts the resistance 69 which isin series with the instrument 57. I The removal of the resistance 69 allows an additional amount of current to flow through the instrument. This indicates that another subscriber is listening to the program. It will be understood that the same program setmay be seized through other connectors, each of which is provided with a resistance 69 in series with the instrument. 57.

It was noted hereinbefore that the springs number for calling an operator.

20 and 21 are closed on the completion of dial- The key 8 also opens the contacts 23 and 24 P opening the circuit of the relay 27. The bridge 25 comprising a condenser and an impedance coil serves to sustain the current il the line to prevent disagreeable noise, due to the operation of the key 8.

Relay 27 in releasing causes the release of relay 28. Rela 28 completes a circuit from battery throug the winding-of magnet 33, closed vertical ofi-normal contact 35, back contacts of relays 28 and 27'to ground. Mag-'- net 33 operates and locks to ground through its own front contact. Magnet 33 causes the release of connector switch Q. When the switch is released, the contact 35 opens-permitting the magnet to release. The side switch. is also restored in a manner well known in the art.

Assume next that the subscriber wishes to call the operator at the central oflice. He actuates the key 8 to initiate the call and manipulates the dial 6 in accordance withthe The connector' C is operated as above described to tion the 'brusheson a set select the proper level and is rotated to'posioit terminals 70, 71, 72, and 73, representing the first-operators circuit 60. If the operators circuit 60 is idle, noground potential exists onv the terminal 73 and the escape magnet 30 releases the side switch into position 3. In this position a circuit is closed from ground through the side switch arm 43,-brush 50,'to the multiple terminal 73, to render the trunk busy to other connectors.

Another circuit is completed from battery through the resistance 74, terminal 72, brush 49, wiper 42, winding of relay 36' to ground.

Relay 36 reverses the direction offlow of current over the-line 1 causing the polarized relay!) to operate. Relay 5 disconnects the program receiving set and renders the telephone 4' efiective. The circuit for talking current may be traced over the tip side of the line through the windings of relay 5, contact I on of said relay, "thence throu h the telephone set 4 and returning over t e lower side of the line'. The subscriber may now converse with the operator.

If the first operators trunk 60 isvbusy, when the rotary movement. is completed, a

the magnet 30, wiper 43, in position 2, brush 50, tothe grounded terminal 73. Magnet 30 remainsenergized and as soon as relay 29 releases, a circuit is closed from battery through the winding of magnet 32, contact of said magnet, contact of magnet 30 to ground on the back contact of relay 29. The rotarymagnet 32 interrulpts its own circuit and steps the connector from one set of terminals to another until an idleoperators trunk is reached. When an idle trunk is found, the

magnet 30 releases opening the circuit of magnet 32 and moving the side switch into osition 3.

i the central ofiice for sending programs over said line, a program receiving set and a telephone set at the substation, an operators position, automatic switches, means controlled by the, subscriber for setting said switches to select any one of said programs or the operators position, and means responsive to the selection of the operators position for renderin said program receiving set inefl'ective and set. i 1

2. In combination, a central oflice, a subscribers line terminating therein, means at p the central oflice for sending programs over said line, a program receiving set at the substation normall connected to the line, a telephone set at t ev substation, an operators position, automatic switches, an impulse sender at the substation controlled by the subscriber for setting said switches to select one ofsaid programs or to select the operators position, and m'eans at the 'substation responsiveito the selection of the operators position for rendering the program receiving set ineffective andv for rendering effective said telephone set.

3. In combination, a central oflice having 1 subscribers lines terminating therein, means at the central oflEice for sending programs The subscriber may converse with the opor' rendering efi'ective said telephone over said lines, a program receiving set ambm a telephone set at each substation, an operators position andautomaticswitches at the central oflice, means controlled by a subscriber for setting said automatic switches to select. any one of the programs and to select the operators position, means controlled by oneof the switches responsive to the selectionof the operators position forsending a signal back .to the substation, and cans controlled holding circuit is closed from battery through by said signal for rendering he program re- 13o effective.

ceiving set ineffective and the telephone set 4. In combination, a central office having a subscribers line terminating therein, means at the central ofiice for sending programs over said line, a program receiving set and a telephone set at the substation, an operators position and automatic switches at the central oflice, means controlled by the subscriber for setti'ngsaid switches to select either a. program or the operators position, means responsive to the selection of the operator for reversing the polarity of current'flowing in said line, and a polarized relay at the substation responsive to such reversal for rendering the program receiving set ineffective and the telephone set effective.

5. In combination, a central office having automatic switches therein, a subscribers line leading to the central oifice, a transmitter at the substation having interrupting contacts for sending impulses to operate said switches, a set of contacts for shunting the interrupting contacts, a progressively movable device,

a switch. for closing the line circuit and for rendering said device operative, and means for advancing said device responsive to adefinite number of manipulations of the transmitter to close said shunting contacts.

6. In combination, acentral ofice having automatic switches, a subscribers line leading to the central oflice, a transmitter at the-substation having a dial and a set of interrupting springs for sending impulses to operate said switches, a set of contacts for shunting said springs to prevent the sending of further impulses, a progressively movable device, a switch for closing the line circuit and forstoring energy to operate said device, and means for advancing said device responsive to a definite number of manipulations of said dial to close said shunt contacts.

7 In combination, a central otfice having automatic switches therein, a subscribers line for connecting the line to oneof said equipments, an indlcating instrument having a resistance in circuit therewith, and means forv 10. In combination, a central oflice having program distributingequipments, subscribers lines, selective switches controlled by the subscribers for extending their lines to said equipments, "indicating instruments, one for each equipment, resistances in c rcuit with said instruments, and means controlled by each of said switches on selecting an equip ment for shunting a portion ofthe resistance in series with the corresponding instrument.

In witness whereof, I hereunto subscribe my name this 19th day of August A. D., 1927.

CHARLES L GOODRUM.

leadin to the central oflice, a transmitter at the su station having interrupting springs I for sending impulses to operate said switches,

a number of program transmitting mecha-' msms selectable by said switches, a set of contacts for shunting the interrupting springs to prevent the sending of further impulses after a program'hasbeen selected, an escapement device operable at each manipulation of the transmitter, a switch for closin the line circuit and for storing energy said escapement, means for causing the ad- Vance of'said escapement to close said shunt contacts in response to a definite number of, manipulations of said transmitter, and means for preventing reaction disturbances on said linei when said last mentioned switch is operate 8. In combination, a central oflice having a plurality of program distributing equipments, a subscribers line, a selective switch or operating 

